Process of shrinkproofing regenerated cellulose fabric with alkoxymethylene quaternary ammonium compositions and product produced therefrom



Unite This invention relates to a method for the treatment ofregenerated cellulosic textile materials in order to improve theirdimensional stability. Also included'within the purview of the inventionare the dimensionally stable fabrics resulting from this treatment. Thisapplication is a continuation-in-part of our co-pending applications S.N. 121,633' (now Patent No. 2,681,342) and S.'N. 121,634 (nowabandoned), both filed October 15, 1949.

-Heretofore, several methods have been used for shrink proofingregenerated cellulosic fabrics (i. e.,rayons prepared by the viscose orcuprammonium processes, etc.). One of the methods involves applicationof resins, such as melamine-formaldehyde, urea-formaldehyde oracetone-formeldehyde polymers to the fabric. is subject to manydisadvantage-s, among them the serious shortcoming of increasing theweight of the fabric and thus detracting from its original hand anddrape qualities. In addition, this treatment changes the nature of thefabric so that it is prone to pick up chlorine-during laundering. Theresin finish is gradually removed as the fabric is laundered, untilfinally its effectsare substantially completely lost and the fabricshrinks excessively.

Another shrinkproofing method involves treatment of the fabric withglyoxal. This method likewise has many disadvantages among which may bementioned its tendency to render the fabric less susceptible to directdyeing, as well as its tendency to substantially destroy the tensilestrength of the fabric. In addition, the glyoxal process is adaptable toonly a carefully prepared fabric which may be dyed with a relativelysmall group of fast dyes.

A third method is described in U. S. Patent No. 2,351,581. I It involvesthe use of certain quaternary ammonium compounds having oxymethyl groupsas N-substituents. This process is subject to the disadvantages ofimparting hydrophobic characteristics to the fabric and results in alowered moisture pickup. Furthermore, fabrics so-treated exhibit poorand uneven dye absorption.

It is an object of the present invention to avoid the foregoing andother disadvantages of prior art processes by means of a new method forimproving dimensional stability which involves the use of a new class ofcompositions obtained as described in our co-pending application S. N.121,633.

This method ats Pat n V hance the shrinkproofing properties of theproducts used. 1

A further object is to devise a shrinkproofing method mated with certainquaternary ammonium compositions,

followed byframing and curing of the impregnated material. In accordancewith my invention I have found that if the fabric is treated asdescribed above, it'not only retains practically all of its originaldesirable characteristics but is rendered surprisingly shrinkproof andpH of 3 or lower preferably about 23) at ambient or slightly elevated(i. e. about 20 C. to C.) temperatures. These compositions are allcharacterized by the presence of quaternary ammonium halides having amethoxymethyl group as an N-substituent.

Although it might appear that reaction of a tertiary amine with achloromethyl ether would yield similar products, it has been found thatmy method, involving the use of an anhydrous tertiary amine salt,methanol and formaldehyde is not only cheaper but produces a mixture ofby-products which appear to substantially en- It is evident from theforegoing that a relatively narrow class of compositions containingquaternary ammonium halides with N-methoxymethyl substituents may beemployed in accordance with this invention. While all of thesecompositions will improve the dimensional stability of regenerated ormodified cellulosic fabrics, they will not do so to the same extent.prefer to use those compositions obtained using, as the tertiary aminesalt reactant, picoline hydrochloride, pyridine hydrochlorideor dimethylbenzyl amine hydrochloride; or mixtures predominating in one or more ofthese salts.

My invention as to process is not limited to any narrowly definedconditions. Nevertheless, for best results I prefer to impregnate thefabric by means of a solution containing from about 5 to about 10% byweight of the shrinkproofing compositions; and it is essential tomaintain the pH of the solution within the range of about 2 to 5. Theexcess solution is advisably removed from the impregnated fabric, .forexample, on padder or squeeze rolls, and the treated fabric framed tothe desired dimensions. Thereafter, the impregnated fabric is cured atelevated temperatures for a short period, during which a chemicalreaction probably occurs between the fabric and the shrinkproofingcomposition. While the conditions of this curing operation are notcritical, I prefer to employ temperatures within the range of about C.

to about C. and times extending from about 2 to 10 g minutes.

I do not know the precise mechanism of the reaction whereby theregenerated or modified cellulosic textiles are dimensionally stabilizedby my shrinkproofing compositions, and do not wish to be restricted toany theory; nevertheless, it is my belief that these reagents react withthe cellulosic material to form a derivative of the cellulose molecule.

Following in tabular form is the results of comparative tests made usingthe compositionsof this invention, obtained as described in Example III,infra, under acid' and non-acid conditions:

Type of Matt. Percent pH Pick-up, Shrinkage,

- percent percent For optimum results'l Theinvention may be more readilyunderstood by a consideration of the-following illustrativeexampleswhere in quantities are stated in parts by weight unlessotherwise noted.

Example I (A) To 4219 parts of refined beta-gammapicoline was added withstirring 4,627 parts of concentrated hydrochloric acid, sp. gr. 1.88, ata rate'such that. the temperature of the mixture did not exceed 100 C.The. mixture was decolorized with carbon and then heated upto 200 C. todrive off all the water and obtain substantially an anhydrous salt.After the salt had cooled to.room.tem-

perature, 1452 parts of methanol was introduced. The

pH of a 1% solution was 4.0. This value was adjustedto 2.6 by additionof 95 partsof concentrated hydrochloric acid... Then, 1360 parts ofparaformaldehyde was added. The reaction temperature Was maintained at50 C. until the product dissolved perfectly clear in water,,whichrequired about 4 hours. Unreacted methanol, together with the methylalwhich formed. as a. by-product, were removed through distillation. Theyield of finalproduct was. 7794 parts.

, The final products (a mixture containing -methoxy methylenebeta-gamma-picolinium chloride) produced. as.

aforesaidare characterized by being semi-solidat room temperature(crystalline material admixed withliquid). At about 50 C. theycompletely liquify toform. a lightamber-colored, water-clear, liquid.They arecompletely soluble in water in all proportions.

(B) A measured sample of Fuji fabric (all-rayon),

desized and scoured, was padded through a 7.5% aqueous solution of acomposition obtained as described in (A), which had been adjusted to pH4.5, then framed to approximately original size and cured for about 5minutes at 150 C. The cured fabric, after washing according to AATCCStandard Wash Test No. 3, shrank warpwise 0.3%. The untreated controlunder the same wash test shrank 8.0%. The loss in tensile strength ascompared with control was.4.5%.

Ei'ample- II (A) One hundred and eighty-six parts of mixed picolines and64 parts of methanol were treated with anhydrous hydrogen chloride atsuch a rate that the temperature of reaction did not exceed 70 C. untila total of 71 parts of gas had been introduced. The time required wasapproximately three hours. The pH of a 1% solution was,2.1. The mixturewas then allowed to cool to 40 C. when 60 parts of paraformaldehyde wasintroduced. The reactionmixture wasmechanically stirred at 40.to 50 C.

until. the solution dissolved completely in water.

(B) A measured sample of greige Fuji fabric (allrayon) was treated withaqueous solution ofthe composition obtained as described in (A), whichhad been adjusted to pH 2.9, passed through squeeze rolls toremoveexcess solution, then framed to original dimensions and cured for5 minutes at 150 C. In .the standard wash test, the treated sampleshrank 4.4% warp direction and the untreated control shrank 17%. Thepercent loss in tensile strength of the treated sample was 6.

Example III (A) To1158 partsof pyridine, there was..added 2045 partsconcentratedihydrochloric acid (36%) gradually and with stirring. Themixture was heated up to about 200 C. to drive off all the'water andunreacted pyridine; To the cooled pyridinium hydrochloride was added 74parts methanol. The solution was adjusted to pH 2.4. Then 55 parts ofparaformaldehyde was introduced. The mixture was stirred at roomtemperature for 4 hours, then heated to distill otf methylal andunreacted methanol. The yield was 273 parts.

The final products (a mixture containing methoxy methyl pyridiniumchloride) produced as aforesaid has the same general appearance andproperties as the mixture described in Example I.

(B) A measured sample of desized Fuji fabric (all rayon) was immersed ina 10% aqueous solution, adjusted to a pH of 2.1, of the compositionobtained as described in (A). It was then squeezed, framed to themeasured dimensions, dried, and cured for 6 minutes at C. After washing,the treated sample shrank 0.1%; whereas the control shrank 7.5%. Therewas a 7.5% loss of tensile strength.

Example V (A) To 135 parts of benzyl dimethyl amine was-added gradually102.2 parts of concentrated hydrochloric acid (36%).- The solution washeated under slight vacuum to remove 55 parts as distillate.- To theconcentrated salt solution, there was then added 32 parts of methanol.Heatingwas required to effect complete solution. The pH of a one percentsolution was 2.2. Then at about 60 C., 30 parts of para-formaldehyde wasintroduced with stirring; The solution became clear in about one hour.

(B) A measured sample of g-reige, all rayon broadcloth was treated witha 10% aqueous solution, of pH 2.5, of After the composition obtained asdescribed in- (A). passing through squeeze rolls, it was framed 'tooriginal dimensions, and cured at C. for 5' minutes.- The for thetertiary amine portion of the reactant any of the I following tertiaryamines: dimethyl pyridine, ethyl pyridine, trimethyl pyridine, ethylmethylpyridine; propyl pyridine, tetramethyl pyridine, ethyl-dimethylpyridine, quinoline, isoquinoline, diethyl benzyl amine, dimethyl benzylamine, methyl benzyl dimethyl'amine, dirnethyl benzyl dirnethyl amine,ethyl methyl benzyl amine, methyl propyl benzyl amine, triethyl amine,dimethyl-isobutyl amine, and the like. These amines are all simpletertiary amines and in each instance'the quaternary-ammoniumcompositions formed therefrom have amethoxy methyl group as anN-substituent. Their anions are advisably chloride, but it iscontemplated that other halogens or hydroxyl groups may serve as theanion;

Where the compositions are not readily soluble in water they may bedissolved in suitable inert organic solvents or mixtures thereof. As ageneral rule however, I prefer to apply the compositions from aqueoussolution and, hence, recommend those which are soluble irr-water. Bymeans of this invention an entirely new class of shrinkproofingagents-is made available to the manufacturer. Unlike the agents of theprior art these materials do not substantially increase the weight ordetract from the drape and hand qualities of the fabrics. Likewise, theydo not destroy the tensile strength of the fabric or otherwiseappreciably affect their desirable qualities. They are practiallypermanent and so far as I am aware are easier to apply in process thanany heretofore used. They may be applied usiugexisting textile machineryand are inexpensivein'comparison with many of theagents now in commonuse. Of additional importance is the fact thatthe compositions of thisinvention will notappreciably affect the "dyeing properties of thefabric.

As manyapparently widelyditferent embodiments of this invention may bemade without-departing from the spirit and scope hereof, it is to beunderstood that the invention is not limited to the specific embodimentshere of except as defined in the appended claims.

I claim:

1. A process for shrink proofing regenerated cellulose fabric whichcomprises impregnating said fabric, at a pH of about 2-5 with at leastof an aqueous solution of an alkoxymethylene quaternary ammonium shrinkproofing composition obtained by reacting an anhydrous tertiary aminehydrohalide with methanol and p-araformaldehyde at a pH of about 2-3 attemperatures between about and C., framing the impregnated material tothe original dimension and curing it by heating at elevated temperaturesuntil a shrink proof regenerated cellulose fabric is obtained.

2. The process of claim 1 wherein the aqueous solution contains about 5to 10% of said shrinkproofing composition.

3. The process of claim 2 wherein curing is effected at a temperature ofbetween about C. and C.

4. A shrink proof regenerated cellulose textile material produced by theprocess defined in claim 1.

References Cited in the file of this patent UNITED STATES PATENTS2,125,901 Evans et al. Aug. 9, 1938 2,243,682 Reyonlds et al May 27,1941 2,282,702 Bock et al May 12, 1942 2,330,775 Bock et -al. Sept. 28,1943 2,351,581 Bock et a1. June 20, 1944 2,680,057 Janes June 1, 19542,681,342 Mussser June 15, 1954 FOREIGN PATENTS 426,482 Great BritainMar. 28, 1935 OTHER REFERENCES Journal of the Textile Institute, April1946, page A173, Cellulose Materials: Vulcanisation.

1. A PROCESS FOR SHRINK PROOFING REGENERATED CELLULOSE FABRIC WHICHCOMPRISES IMPREGNATING SAID FABRIC, AT A PH OF ABOUT 2-5 WITH AT LEAST5% OF AN AQUEOUS SOLUTION OF AN ALKOXYMETHYLENE QUATERNARY AMMONIUMSHRINK PROOFING COMPOSITION OBTAINED BY REACTING AN ANHYROUS TERTIARYAMINE HYDROHALIDE WITH METHANOL AND PARAFORMALDEHYDE AT A PH OF ABOUT2-3 AT TEMPERATURES BETWEEN ABOUT 20* AND 80*C., FRAMINING THEIMPREGNATED MATERIAL TO THE ORIGINAL DIMENSION AND CURING IT BY HEATINGAT ELEVATED TEMPERATURES UNTIL A SHRINK EGENERATED CELLULOSE FABRIC ISOBTAINED.